Red panda behaviour was studied in the Wolong Reserve, Sichuan, China to understand better the ecology of this herbivorous member of the Carnivora. Leaves of montane bamboo were the most common food in all months (93.7% of 791 droppings), supplemented in spring with bamboo shoots, and in late summer with arboreal fruits. Home-range estimates by radiotelemetry for one adult female (94 ha) and one adult male (111 ha) most closely approximated allometrically-predicted range size for omnivores. Pandas were active45–49% of the time, with highest levels in April, and, for the female in summer when lactating. Activity was higher in daylight than at night, especially in summer, coincident with arboreal foraging. The hypothesis that pandas rest in direct sunlight in winter to minimize heat loss while reducing peripheral circulation, was inferentially supported by their spending significantly more time resting on clear compared to overcast winter days. The red panda's anatomy, diet and low metabolic rate suggest an arboreal folivorous lineage incorporating terrestrial foraging to capitalize on a super-abundant food resource–bamboo. Energy content of the annual recruitment of bamboo leaves within home ranges was substantially greater than annual energy requirements predicted allometrically. Gross food availability was not limiting to the radio-collared pandas, but may have been so in unoccupied habitats with a lower bamboo density following the bamboo die-back. Maternity den trees are probably a limiting resource in clearcut and deciduous forest habitats.